U.S. patent number 10,837,797 [Application Number 16/173,965] was granted by the patent office on 2020-11-17 for method for sorting unsystematic environment risk of underground storage tank systems.
This patent grant is currently assigned to Environmental Protection Administration, R.O.C.. The grantee listed for this patent is Environmental Protection Administration, R.O.C.. Invention is credited to Fu-Chieh Chang, Chun-Ming Chen, I-Hsing Chen, Shyh-Wei Chen, Yu-Yun Hsieh, Hsuan-Ting Lai, Chun-Chun Lin.
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United States Patent |
10,837,797 |
Chen , et al. |
November 17, 2020 |
Method for sorting unsystematic environment risk of underground
storage tank systems
Abstract
A method for sorting unsystematic environment risk of
underground storage tank systems includes: generating an
unsystematic environmental site assessment priority list for the
underground storage tank systems using a risk weight assessment
module based on facility level factor data and operational status
factor data of each underground storage tank system; obtaining an
actual soil gas detection data for each underground storage tank
system after conducting an environmental site assessment on the
priority list; and generating an investigation list according to
the contamination potential assessment result of each underground
storage tank system using a contamination potential assessment
module based on the actual soil gas detection data as a basis for
subsequent investigation and regulation on the underground storage
tank systems.
Inventors: |
Chen; Shyh-Wei (Taipei,
TW), Chen; Chun-Ming (Taipei, TW), Chen;
I-Hsing (Taipei, TW), Chang; Fu-Chieh (Taipei,
TW), Lai; Hsuan-Ting (Taipei, TW), Hsieh;
Yu-Yun (Taipei, TW), Lin; Chun-Chun (Taipei,
TW) |
Applicant: |
Name |
City |
State |
Country |
Type |
Environmental Protection Administration, R.O.C. |
Taipei |
N/A |
TW |
|
|
Assignee: |
Environmental Protection
Administration, R.O.C. (Taipei, TW)
|
Family
ID: |
69189116 |
Appl.
No.: |
16/173,965 |
Filed: |
October 29, 2018 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20200041305 A1 |
Feb 6, 2020 |
|
Foreign Application Priority Data
|
|
|
|
|
Aug 3, 2018 [TW] |
|
|
107127079 A |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G06Q
50/06 (20130101); B65D 88/76 (20130101); B65D
90/50 (20130101); G01D 1/00 (20130101); G06Q
10/0635 (20130101) |
Current International
Class: |
G06F
11/30 (20060101); B65D 88/76 (20060101); B65D
90/50 (20190101); G01D 1/00 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Huynh; Phuong
Attorney, Agent or Firm: Marquez; Juan Carlos A. Marquez IP
Law Office, PLLC
Claims
What is claimed is:
1. A method for sorting unsystematic environment risk of
underground storage tank systems, comprising: a preparation step,
providing a baseline database for the underground storage tank
systems, the baseline database comprising facility level factor
data and operational status factor data for each underground
storage tank system; an unsystematic environment risk assessment
step, generating an unsystematic risk assessment result for each
underground storage tank system using an entropy weight assessment
module based on the facility level factor data and the operational
status factor data of the baseline database; an environmental site
assessment step, generating an environmental site assessment list
based on the unsystematic risk assessment result and obtaining an
actual soil gas detection data for each underground storage tank
system in the environmental site assessment list; a contamination
potential assessment step, generating a contamination potential
assessment result using a contamination potential assessment module
based on the actual soil gas detection data for each underground
storage tank system; and a risk control step, generating an
investigation list according to the contamination potential
assessment result of each underground storage tank system as a
basis for subsequent investigation and regulation on the
underground storage tank systems.
2. The method according to claim 1, wherein the facility level
factor data is selected from a group consisting of a storage tank
material factor (A.sub.1), a storage tank protection measure factor
(A.sub.2), a pipeline material factor (A.sub.3) and a pipeline
protection measure factor (A.sub.4), and the operational status
factor data is selected from a group consisting of a monthly
average gasoline quantity factor (B.sub.1), a storage tank usage
time factor (B.sub.2) and a pipeline usage time factor
(B.sub.3).
3. The method according to claim 1, wherein the unsystematic risk
assessment result consists of an unsystematic risk score (URS) and
an unsystematic risk level determined by the unsystematic risk
score (URS), wherein the environmental site assessment list is
determined by the unsystematic risk level.
4. The method according to claim 3, wherein the unsystematic risk
score (URS) is a sum of the following factors: a product of the
storage tank material factor (A.sub.1) and a storage tank material
weight factor (W.sub.A1); a product of the storage tank protection
measure factor (A.sub.2) and a storage tank protection measure
weight factor (W.sub.A2); a product of the pipeline material factor
(A.sub.3) and a pipeline material weight factor (W.sub.A3); a
product of the pipeline protection measure factor (A.sub.4) and a
pipeline protection measure weight factor (W.sub.A4); a product of
the monthly average gasoline quantity factor (B.sub.1) and a
monthly average gasoline quantity weight factor (W.sub.B1); a
product of the storage tank usage time factor (B.sub.2) and a
storage tank usage time weight factor (W.sub.B2); and a product of
the pipeline usage time factor (B.sub.3) and a pipeline usage time
weight factor (W.sub.B3).
5. The method according to claim 4, wherein the storage tank
material factor (A.sub.1) is a relative risk of a plurality of
specified categories of storage tank materials, the storage tank
protection measure factor (A.sub.2) is a relative risk of a
plurality of specified categories of storage tank protection
measures, the pipeline material factor (A.sub.3) is a relative risk
of a plurality of specified categories of pipeline materials, the
pipeline protection measure factor (A.sub.4) is a relative risk of
a plurality of specified categories of pipeline protection
measures, the monthly average gasoline quantity factor (B.sub.1) is
a relative risk of a plurality of specified intervals of monthly
average gasoline quantity, the storage tank usage time factor
(B.sub.2) is a relative risk of a plurality of specified intervals
of storage tank usage time, and the pipeline usage time factor
(B.sub.3) is a relative risk of a plurality of specified intervals
of pipeline usage time.
6. The method according to claim 4, wherein the storage tank
material weight factor (W.sub.A1), the storage tank protection
measure weight factor (W.sub.A2), the pipeline material weight
factor (W.sub.A3), the pipeline protection measure weight factor
(W.sub.A4), the monthly average gasoline quantity weight factor
(W.sub.B1), the storage tank usage time weight factor (W.sub.B2)
and the pipeline usage time weight factor (W.sub.B3) are calculated
by an entropy weight method according to the baseline database for
the underground storage tank systems.
7. The method according to claim 1, wherein the environment site
assessment list comprises: a high level unsystematic risk
environmental site assessment list including underground storage
tank systems recommended for performing an environmental site
assessment with priority; a medium-high level unsystematic risk
environmental site assessment list including underground storage
tank systems determined for sequentially performing an
environmental site assessment based on the unsystematic risk score
(URS) of each underground storage tank system; a medium level
unsystematic risk environmental site assessment list including
underground storage tank systems recommended for enhancing
self-management; and a low level unsystematic risk environmental
site assessment list including underground storage tank systems
that have no significant impact on the public and environment and
are no need to further perform environmental site assessment.
8. The method according to claim 1, wherein the contamination
potential assessment result comprises a contamination potential
level (CPL), wherein the investigation list is determined by the
contamination potential level (CPL).
9. The method according to claim 8, wherein the contamination
potential level (CPL) is obtained by calculating a soil gas risk
factor (S.sub.soil gas).
10. The method according to claim 9, wherein the soil gas risk
factor (S.sub.soil gas) is obtained by summing up a gasoline gas
concentration warning factor (I.sub.1), a gasoline gas
concentration alarm factor (I.sub.2), a plurality of gasoline gas
concentration alarm factor (I.sub.3), a gasoline characteristic
compound factor (I.sub.4), and a methane concentration alarm factor
(I.sub.5), wherein the preceding factors are obtained by
calculating the actual soil gas detection data.
11. The method according to claim 8, wherein the investigation list
comprises a high environmental risk level list including
underground storage tank systems recommended for performing an
immediate site assessment.
Description
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority of Taiwanese patent
application No. 107127079, filed on Aug. 3, 2018, which is
incorporated herewith by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for sorting unsystematic
environment risk of underground storage tank systems to regulate
the underground storage tank systems with a high environment risk
level.
2. The Prior Arts
An underground storage tank system refers to storage tanks for
storing gasoline/diesel, and pipelines connected to the storage
tanks for loading and unloading gasoline/diesel, which are buried
under the ground surface. These underground storage tank systems
are mainly used in gas stations, and come second used in factories.
Since the underground storage tank system is buried under the
ground surface for a long time, corrosion and leakage are not easy
to be detected. Hence, when leakage pollution is eventually
detected, there may result in a serious and irreversible
environmental damage. Furthermore, leakage pollution is relevant
with the operation of the underground storage tank systems, and
thus its risk characteristic is belonged to a non-systematic risk.
Each individual underground storage tank system has a different
environmental risk level. It is necessary to screen out the
underground storage tank systems with a high environmental risk
level in a most effective way to achieve an early detection and
early remediation.
Regarding how to screen out the underground storage tank systems
with a high environmental risk level, the traditional practice is
to generate an investigation priority list based on the
establishment date of the gas stations (factories) recorded in
business licenses or factory registration data, and then
investigate and regulate the gas stations (factories) in the
investigation priority list. Although there exists a certain
correlation between the age of the gas stations (factories) and
leakage pollution, one cannot say an underground storage tank
system of a gas station (factory) with an operation period of more
than 40 years definitely has leakage pollution or an underground
storage tank system of the gas station (factory) with an operation
period of less than 10 years is definitely leak-free and
pollution-free. In considering that the underground storage tank
systems may undergo equipment replacement during the operation
period, the environmental risk level of an underground storage tank
system determined merely based on the gas station (factory) age
factor cannot reflect the actual environmental risk level of the
underground storage tank system.
Therefore, it would often require too much manpower, resource and
time to regulate a large number of underground storage tank systems
operated in various ways by using the traditional method.
SUMMARY OF THE INVENTION
In view of the above-mentioned problems resulted in the traditional
environment risk control method, an objective of the present
invention is to provide a method for sorting unsystematic
environment risk of underground storage tank systems, which can
generate a risk assessment result closer to the actual condition of
the underground storage tank systems so as to efficiently conduct
subsequent investigation and regulation on the underground storage
tank systems.
According to the present invention, a method for sorting
unsystematic environment risk of underground storage tank systems
includes: a preparation step, providing a baseline database for the
underground storage tank systems, the baseline database including
facility level factor data and operational status factor data for
each underground storage tank system; an unsystematic environment
risk assessment step, generating an unsystematic risk assessment
result for each underground storage tank system using an entropy
weight assessment module based on the facility level factor data
and the operational status factor data of the baseline database; an
environmental site assessment step, generating an environmental
site assessment list based on the unsystematic risk assessment
result and obtaining an actual soil gas detection data for each
underground storage tank system in the environmental site
assessment list; a contamination potential assessment step,
generating a contamination potential assessment result using a
contamination potential assessment module based on the actual soil
gas detection data for each underground storage tank system; and a
risk control step, generating an investigation list according to
the contamination potential assessment result of each underground
storage tank system as a basis for subsequent investigation and
regulation on the underground storage tank systems.
Preferably, the facility level factor data is selected from a group
consisting of a storage tank material factor (A.sub.1), a storage
tank protection measure factor (A.sub.2), a pipeline material
factor (A.sub.3) and a pipeline protection measure factor
(A.sub.4), and the operational status factor data is selected from
a group consisting of a monthly average gasoline quantity factor
(B.sub.1), a storage tank usage time factor (B.sub.2) and a
pipeline usage time factor (B.sub.3).
Preferably, in this embodiment, the unsystematic risk score (URS)
is a sum of the following factors: a product of the storage tank
material factor (A.sub.1) and a storage tank material weight factor
(W.sub.A1); a product of the storage tank protection measure factor
(A.sub.2) and a storage tank protection measure weight factor
(W.sub.A2); a product of the pipeline material factor (A.sub.3) and
a pipeline material weight factor (W.sub.A3); a product of the
pipeline protection measure factor (A.sub.4) and a pipeline
protection measure weight factor (W.sub.A4); a product of the
monthly average gasoline quantity factor (B.sub.1) and a monthly
average gasoline quantity weight factor (W.sub.B1); a product of
the storage tank usage time factor (B.sub.2) and a storage tank
usage time weight factor (W.sub.B2); and a product of the pipeline
usage time factor (B.sub.3) and a pipeline usage time weight factor
(W.sub.B3).
Preferably, the storage tank material factor (A.sub.1) is a
relative risk of a plurality of specified categories of storage
tank materials, the storage tank protection measure factor
(A.sub.2) is a relative risk of a plurality of specified categories
of storage tank protection measures, the pipeline material factor
(A.sub.3) is a relative risk of a plurality of specified categories
of pipeline materials, the pipeline protection measure factor
(A.sub.4) is a relative risk of a plurality of specified categories
of pipeline protection measures, the monthly average gasoline
quantity factor (B.sub.1) is a relative risk of a plurality of
specified intervals of monthly average gasoline quantity, the
storage tank usage time factor (B.sub.2) is a relative risk of a
plurality of specified intervals of storage tank usage time, and
the pipeline usage time factor (B.sub.3) is a relative risk of a
plurality of specified intervals of pipeline usage time.
Preferably, the environment site assessment list includes: a high
level unsystematic risk environmental site assessment list
including underground storage tank systems recommended for
performing an environmental site assessment with priority; a
medium-high level unsystematic risk environmental site assessment
list including underground storage tank systems determined for
sequentially performing an environmental site assessment based on
the unsystematic risk score (URS) of each underground storage tank
system; a medium level unsystematic risk environmental site
assessment list including underground storage tank systems
recommended for enhancing self-management; and a low level
unsystematic risk environmental site assessment list including
underground storage tank systems that have no significant impact on
the public and environment and are no need to further perform
environmental site assessment.
Preferably, the actual soil gas detection data obtained from the
environmental site assessment list includes a soil gas monitoring
well gasoline gas concentration detection data and a soil gap gas
compound qualitative detection data. The soil gas monitoring well
gasoline gas concentration detection data consists of: the
percentage of lower explosive limits (% LEL) (for each soil gas
monitoring well) detected by a flammable gas detector; an gasoline
gas concentration value detected by a photo ion detector (PID); and
an gasoline gas concentration value detected by a flame ionization
detector (FID). The soil gap gas compound qualitative detection
data consists of: a methane concentration value, a methyl
tert-butyl ether concentration value, a benzene concentration
value, a toluene concentration value, an ethylbenzene concentration
value, an xylene concentration value, a normal decane concentration
value, and a naphthalene concentration value detected by a gas
chromatography/flame ionization detector (GC/FID) for each soil gap
gas sample.
Preferably, the risk control measures are based on the following
contamination potential levels (CPL): a grade A contamination
potential level list includes underground storage tank systems
recommended for immediately performing an environmental site
assessment; a grade B contamination potential level list includes
underground storage tank systems recommended for performing a
periodical follow-up soil gas detection; and a grade C
contamination potential level list includes underground storage
tank systems recommended for no need to perform further control due
to no leakage pollution temporarily.
According to the present invention, a method for sorting
unsystematic environment risk of underground storage tank systems
provides a risk assessment result closer to the actual condition of
the underground storage tank system, including contamination
potential levels and an investigation list determined by the
contamination potential levels, so as to efficiently conduct
subsequent investigation and regulation on the underground storage
tank systems and thus save much manpower, resource and time.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be apparent to those skilled in the art
by reading the following detailed description of a preferred
embodiment thereof, with reference to the attached drawings, in
which:
FIG. 1 is a diagram illustrating a method for sorting unsystematic
environment risk of underground storage tank systems.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The accompanying drawings are included to provide a further
understanding of the invention, and are incorporated in and
constitute a part of this specification. The drawing illustrates
embodiments of the invention and, together with the description,
serves to explain the principles of the invention. It is worth
noting that the language of "include" in the specification is not
used to limit the embodiments and should be interpreted as
"include, but not limited to".
Referring to FIG. 1, it is a diagram illustrating the steps of a
method for sorting unsystematic environment risk of underground
storage tank systems according to the present invention.
Referring to step S10, in a preparation step, facility level factor
data and operational status factor data are provided for each
underground storage tank system. In one embodiment of the present
invention, the facility level factors consist of a storage tank
material factor (A.sub.1), a storage tank protection measure factor
(A.sub.2), a pipeline material factor (A.sub.3) and a pipeline
protection measure factor (A.sub.4), and the operational status
factors consist of an monthly average gasoline quantity factor
(B.sub.1), a storage tank usage time factor (B.sub.2) and a
pipeline usage time factor (B.sub.3).
Referring to the step S20, in an unsystematic environment risk
assessment step, an risk weight assessment module is used to
generate an unsystematic risk assessment result for each
underground storage tank system, wherein the unsystematic risk
assessment result is an unsystematic risk score (URS) and an
unsystematic risk level is determined by the unsystematic risk
score (URS). In one embodiment of the present invention, the risk
weight assessment module utilizes the following equation (1) to
generate the unsystematic risk score (URS).
.times..times..times..times. ##EQU00001##
In the above equation, A.sub.1 is a relative risk of a plurality of
specified categories of storage tank materials; W.sub.A1 is a
storage tank material weight factor; A.sub.2 is a relative risk of
a plurality of specified categories of storage tank protection
measures; W.sub.A2 is a storage tank protection measure weight
factor; A.sub.3 is a relative risk of a plurality of specified
categories of pipeline materials; W.sub.A3 is a pipeline material
weight factor; A.sub.4 is a relative risk of a plurality of
specified categories of pipeline protection measures; W.sub.A4 is a
pipeline protection measure weight factor; B.sub.1 is a relative
risk of a plurality of specified intervals of monthly average
gasoline quantity; W.sub.B1 is a monthly average gasoline quantity
weight factor; B.sub.2 is a relative risk of a plurality of
specified intervals of storage tank usage time; W.sub.B2 is a
storage tank usage time weight factor; B.sub.3 is a relative risk
of a plurality of specified intervals of pipeline usage time; and
W.sub.B3 is a pipeline usage time weight factor.
In the following Tables, Table 1 shows the corresponding relative
risks of the storage tank material factor (A.sub.1); Table 2 shows
the corresponding relative risks of the storage tank protection
measure factor (A.sub.2); Table 3 shows the corresponding relative
risks of the pipeline material factor (A.sub.3); Table 4 shows the
corresponding relative risks of the pipeline protection measure
factor (A.sub.4); Table 5 shows the corresponding relative risks of
the monthly average gasoline quantity factor (B.sub.1); Table 6
shows the corresponding relative risks of the storage tank usage
time factor (B.sub.2) and the pipeline usage time factor (B.sub.3);
and Table 7 shows the weight factor score of the preceding
factors.
TABLE-US-00001 TABLE 1 Storage tank material factors (A.sub.1) and
the corresponding risks The corresponding Types risks of factors
(A.sub.1) Steel 0.989 Glass fiber reinforced plastic (single 0.921
layer) Glass fiber reinforced plastic (double 1.138 layer)
TABLE-US-00002 TABLE 2 Storage tank protection measure factors
(A.sub.2) and the corresponding risks The corresponding Type risks
of factors (A.sub.2) Installing cathodic corrosion 0.983 protection
system Paint coating on the outer layer 1.244 Covering the outer
layer with epoxy 1.382 resin Covering the outer layer with glass
0.691 fiber Covering the outer layer with asphalt 1.176 Covering
the outer layer with 1.185 polyethylene Covering the outer layer
with 0.395 polyurethane Covering the outer layer with an anti-
2.764 corrosion strap Use a secondary barrier protection 0.908 No
proper protection 1.382
TABLE-US-00003 TABLE 3 Pipeline material factors (A.sub.3) and the
corresponding risks Type The corresponding risks of factors
(A.sub.3) Steel 0.996 Glass fiber 1.005 Flexible tube with single
layer 1.701 Flexible tube with double layer 0.928
TABLE-US-00004 TABLE 4 Pipeline protection measure factors
(A.sub.4) and the corresponding risks Type The corresponding risks
of factors (A.sub.4) Installing cathodic corrosion 1.185 protection
system Paint coating on the outer layer 1.448 Covering the outer
layer with 1.082 glass fiber Covering the outer layer with 0.905
polyethylene Covering the outer layer with an 0.991 anti-corrosion
strap Use a secondary barrier 1.244 protection No proper protection
0.819
TABLE-US-00005 TABLE 5 Monthly average gasoline quantity factor
(B.sub.1) and the corresponding risks The corresponding Type risks
of factors (B.sub.1) <100,000 Litre/month 1.474 100,001~200,000
Litre/month 1.325 200,001~300,000 Litre/month 0.633 300,001~400,000
Litre/month 1.050 400,001~500,000 Litre/month 1.053 500,001~600,000
Litre/month 0.819 600,001~700,000 Litre/month 0.790 700,001~800,000
Litre/month 0.488 800,001~900,000 Litre/month 0.873
900,001~1,000,000 Litre/month 1.382 >1,000,001 Litre/month
1.164
TABLE-US-00006 TABLE 6 Storage tank usage time factor (B.sub.2) and
pipeline usage time factor (B.sub.3) and the corresponding risks
Corre- Corre- Storage tank usage sponding Pipeline usage sponding
time factor (B.sub.2) risks time factor (B.sub.3) risks <1,000
days 0.921 <1,000 days 1.106 1,001~2,000 days 0.518 1,001~2,000
days 0.711 2,001~3,000 days 0.721 2,001~3,000 days 0.744
3,001~4,000 days 0.761 3,001~4,000 days 0.833 4,001~5,000 days
0.900 4,001~5,000 days 0.742 5,001~6,000 days 1.169 5,001~6,000
days 1.106 6,001~7,000 days 1.152 6,001~7,000 days 1.463
7,001~8,000 days 1.037 7,001~8,000 days 0.921 8,001~9,000 days
1.814 8,001~9,000 days 1.974 9,001~10,000 days 1.382 9,001~10,000
days 1.626 >10,001 days 0.921 >10,001 days 1.106
The storage tank material weight factor (W.sub.A1), the storage
tank protection measure weight factor (W.sub.A2), the pipeline
material weight factor (W.sub.A3), the pipeline protection measure
weight factor (W.sub.A4), the monthly average gasoline quantity
weight factor (W.sub.B1), the storage tank usage time weight factor
(W.sub.B2) and the pipeline usage time weight factor (W.sub.B3) are
calculated by an entropy weight method using the following
equations (2)-(4) and the values of every weight factors are shown
in the following Table 7.
.times..times..times..times..times..times..times..times..times..times..ti-
mes..times. ##EQU00002##
In the above equations, E.sub.i is an entropy value of the i-th
facility level factor and operating status factor; r.sub.ij is a
standardized score of j-th calculated sample in the i-th facility
level factor and the operating status factor, the standardized
score is calculated by standardizing the corresponding risks; m is
the number of facility level factors and the operating status
factors, the number of factors is seven in the present invention; n
is the number of samples, 340 samples in the present invention; E
is a sum of the entropy values for each facility level factor and
operating status factor; and W.sub.i is a value of each weight
factor.
TABLE-US-00007 TABLE 7 Weight factors W.sub.A1~W.sub.B3 and the
corresponding values Weight factor Corresponding value Storage tank
material (W.sub.A1) 0.002 Storage tank protection measure 0.268
(W.sub.A2) Pipeline material (W.sub.A3) 0.038 Pipeline protection
measure (W.sub.A4) 0.049 Monthly average gasoline quantity 0.156
(W.sub.B1) Storage tank usage time (W.sub.B2) 0.245 Pipeline usage
time (W.sub.B3) 0.241
The following Table 8 shows the unsystematic risk score (URS),
cumulative probability and unsystematic risk level of underground
storage tank systems, wherein a high risk level range is a
unsystematic risk score cumulative probability of more than 90% and
the unsystematic risk score (URS) ranging between 1.3.about.2.0; a
medium-high risk level range is a unsystematic risk score
cumulative probability of 70-90% and the unsystematic risk score
(URS) ranging between 1.1.about.1.3; a medium risk level range is a
unsystematic risk score cumulative probability of 40-70% and the
unsystematic risk score (URS) ranging between 1.1.about.1.3; and a
low risk level range is a unsystematic risk score cumulative
probability of less than 40% and the unsystematic risk score (URS)
ranging between 0.5.about.1.0.
TABLE-US-00008 TABLE 8 Unsystematic risk scores, cumulative
probability and unsystematic risk levels of underground storage
tank systems Unsystematic Unsystematic risk level Cumulative
probability (%) risk score Low risk level 0 0.563 10 0.804 20 0.887
30 0.948 Medium risk level 40 0.996 50 1.043 60 1.087 Medium-high
risk level 70 1.139 80 1.230 High risk level 90 1.306 100 1.953
Referring to the step S30: in an environmental site assessment
step, the actual soil gas detection data for each underground
storage tank system are obtained. Firstly, an environmental site
assessment list is determined based on the unsystematic risk scores
(URS) and the unsystematic risk levels of underground storage tank
systems. If the unsystematic risk score (URS) ranges between
1.3.about.2.0, the underground storage tank system is determined as
the high level environmental site assessment list. If the
unsystematic risk score (URS) ranges between 1.1.about.1.3, the
underground storage tank system is determined as the medium high
level environmental site assessment list. If the unsystematic risk
score (URS) ranges between 1.0.about.1.1, the underground storage
tank system is determined as the medium level environmental site
assessment list. If the unsystematic risk score (URS) ranges
between 0.5.about.1.0, the underground storage tank system is
determined as the low level environmental site assessment list.
Then, the actual soil gas detection of the underground storage tank
system in the high level environmental site assessment list are
performed in order to obtain the actual soil gas detection data,
which includes a soil gas monitoring well gasoline gas
concentration detection data and a soil gap gas compound
qualitative detection data. The soil gas monitoring well gasoline
gas concentration detection data consists of: the percentage of
lower explosive limits (% LEL) (for each soil gas monitoring well)
detected by a flammable gas detector; an gasoline gas concentration
value detected by a photo ion detector (PID); and an gasoline gas
concentration value detected by a flame ionization detector (FID).
The soil gap gas compound qualitative detection data consists of: a
methane concentration value, a methyl tert-butyl ether
concentration value, a benzene concentration value, a toluene
concentration value, an ethylbenzene concentration value, an xylene
concentration value, a normal decane concentration value, and a
naphthalene concentration value detected by a gas
chromatography/flame ionization detector (GC/FID) for each soil gap
gas sample.
Referring to the step S40, in a contamination potential assessment
step, generating a contamination potential assessment result using
a contamination potential assessment module based on the actual
soil gas detection data for each underground storage tank system in
the step S30, which is a contamination potential level (CPL). CPL
can be obtained from the following equation (5).
.times..times..times..times..gtoreq..times..times..gtoreq..times..times.&-
gt;.times..times..times..times.< ##EQU00003##
In the above equation, S.sub.soil gas is a soil gas risk factor,
which can be obtained from the following equation (6) according to
the actual soil gas risk detection data. S.sub.soil
gas=I.sub.1+I.sub.2+I.sub.3+I.sub.4+I.sub.5 (6)
In the above equation, the soil gas risk factor (S.sub.soil gas) is
a sum of a gasoline gas concentration warning factor (I.sub.1), a
gasoline gas concentration alarm factor (I.sub.2), a plurality of
gasoline gas concentration alarm factor (I.sub.3), a gasoline
characteristic compound factor (I.sub.4), and a methane
concentration alarm factor (I.sub.5), wherein the corresponding
values of the preceding factors are obtained by calculating the
actual soil gas detection data of each storage tank, as shown in
Table 9. It is worth noting that based on the classification and
description of Table 9, a person with ordinary skill in the present
technical field can evaluate each factor according to the actual
soil gas detection data, which has repeatability and
reproducibility.
TABLE-US-00009 TABLE 9 The determination criteria of factors
I.sub.1~I.sub.5 and the corresponding values Corresponding values
Meeting the Not meeting Factors Determination criteria criteria the
criteria Gasoline gas Have at least any one of the following 1 0
concentration detection results: warning factor 1. The gasoline gas
concentration value (I.sub.1) detected by a photo ion detector
(PID) >250 ppmV 2. The gasoline gas concentration value detected
by a flame ionization detector (FID) >250 ppmV. Gasoline gas
Have at least any one of the following 3 0 concentration detection
results: alarm factor (I.sub.2) 1. The percentage of lower
explosive limits (% LEL) >25% 2. The gasoline gas concentration
value detected by a photo ion detector (PID) >500 ppmV 3. The
gasoline gas concentration value detected by a flame ionization
detector (FID) >500 ppmV A plurality of Have at least any two of
the following 6 0 gasoline gas detection results: concentration 1.
The percentage of lower explosive alarm factor (I.sub.3) limits (%
LEL) >25% 2. The gasoline gas concentration value detected by a
photo ion detector (PID) >500 ppmV 3. The gasoline gas
concentration value detected by a flame ionization detector (FID)
>500 ppmV Gasoline The detection result of the soil gap gas 5 0
characteristic compound includes at least two of the compound
factor following compounds: (I.sub.4) methyl tert-butyl ether,
benzene, methyl benzene, ethylbenzene, xylene, normal decane,
naphthalene Methane The methane concentration value 5 0
concentration detected in the soil gap gas compound alarm factor
(I.sub.5) >2,000 ppmV
Referring to the step S50: in a risk control step, an investigation
list is generated according to the contamination potential
assessment result of each underground storage tank system as a
basis for subsequent investigation and regulation on the
underground storage tank systems. First of all, a risk list is
determined according to the contamination potential level (CPL).
That is, a grade A contamination potential level list is determined
as a high environmental risk level list including underground
storage tank systems recommended for immediately performing an
environmental site assessment; the grade B contamination potential
level list is determined as a medium environmental risk level list
including underground storage tank systems recommended for
performing a periodical follow-up soil gas detection; and the grade
C contamination potential level list is determined as a low
environmental risk level list including underground storage tank
systems recommended for no need to perform further control due to
no leakage pollution temporarily. Table 10 shows risk control
measures for the underground storage tank systems, in which gas
stations A to I represent the underground storage tank systems of
the gas stations.
TABLE-US-00010 TABLE 10 Risk control measures Underground storage
List Type tank system Risk control measures Low environmental Gas
stations No need to further perform risk level list A, B, C, D
environmental site assessment due to no significant impact on the
public and environment Medium Gas stations Need to perform a
periodical follow- environmental E, F, G up soil gas detection risk
level list High environmental Gas stations Need to immediately
perform an risk level list H, I environmental site assessment
The method for sorting unsystematic environment risk for
underground storage tank systems according to the present invention
provides the following advantages: the investigator can obtain a
preliminarily screened environmental site assessment list according
to the unsystematic environment risk assessment steps, and thus
narrows the scope of the environmental site risk assessment, obtain
actual gasoline gas detection data from the environmental site
assessment list, and generate a risk assessment result closer to
the actual condition of the underground storage tank systems so as
to efficiently and accurately conduct subsequent investigation and
regulation on the underground storage tank systems.
Although the present invention has been described with reference to
the preferred embodiments thereof, it is apparent to those skilled
in the art that a variety of modifications and changes may be made
without departing from the scope of the present invention which is
intended to be defined by the appended claims.
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